Noise reducing arrangement for use in clothes dryers



NOISE REDUCING ARRANGEMENT FOR, USE IN CLOTHES DRYERS Filed June 11, 1958 2 Sheets-Sheet 1 FIG! 54 mmvron HUGE NE 6. OLTHUJ S H [5 ATTORNEY March 8, 1960 E. G. OLTHUIS NOISE REDUCING ARRANGEMENT FOR USE IN CLOTHES DRYERS Filed June 11, 1958 2 Sheets-Sheet 2 2 8 7 3 3 /A I O UUUUHUUUU UUUUUUUU 91 Y "a h K 9\ A 4 m m A Mu u Em v m m g I l l II t w 6 n PM? Q Q ml 1 wmw m N. 8 u w M Q s w I a 4 [iii a 4 3 Q (((4. M

INVENTOR.

e. OLTHUIS EUGENE HIS ATTORNEY United States PatentO NOISE REDUCING-ARRANGEMENT FOR USE IN a r CLOTHES DRYERS Application June 11, 1958, Serial No. 741,402

Claims. c1. 34-133 This invention relates to apparatus of the type which has a function requiring the exhaustion of gaseous fluid therefrom, such as clothes drying machines for instance, and more particularly to an arrangement for decreasing substantially the noise from such apparatus which normally accompanies the fluid as it flows out through the exhaust. It is a general object of this invention to decrease substantially the noise, in apparatus having a function requiring exhaustion of gaseous fluid, which passes out through the passage provided to exhaust the gaseous fluid.

A further object of the inveniton is to provide noise reducing means which will perform its function without impairment of the proper exhaust of the gaseous fluid.

Yet another object'of the invention is the provision, in apparatus which is contained within a cabinet such as, for instance, clothes dryers, of a system which will eliminate a substantial part of the noise before it escapes from the cabinet so that the noise does not inconvenience the operator when she is in the vicinity of the apparatus.

In carrying out the invention in one form thereof, I provide a suitable cabinet for enclosing apparatus of the type having a function requiring the exhausting of gaseous fluid therefrom. One typical instance of such apparatus is the domestic clothes dryer. A conduit having an end opening to the exterior of the cabinet so as to provide an exhaust path for gaseous fluid extends within the cabinet for at least a portion of its length. In the case of a clothes dryer, the gaseous fluid is, of course, air, which is frequently exhausted directly to the room in which the dryer is positioned. Suitable means, such as the ordinary blower and motor found in domestic clothes dryers, are provided to cause the gaseous fluid to flow through the conduit. My invention is particularly directed toward means for muffiing a substantial part of the noise which would otherwise emerge from the conduit with the fluid. This mufliing arrangement contemplates forming at least part of the conduit wall within the cabinet of a sound transmitting membrane of plastic material, positioned in substantially leakproof relation to the remainder of the conduit so that the sound is transmitted through the membrane but the gaseous fluid is kept within the conduit. To absorb the sound thus being transmitted through the membrane into thecabinet, a mass of sound absorbing material is disposed within the cabinet to assist the natural sound-absorbing action of the various components in the cabinet.

The subject matter which I regard as my invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. My invention, how ever, both as to organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings.

In the drawings,

Fig. 1 is a side elevational view of a clothes dryer typical of theapparatus in which my invention may be Patented Mar. 8, 1960 provided, the view being partially broken away and partially sectionalized to illustrate details of the dryer;

Fig. 2 is a plan sectional view of the dryer with the basket removed and, with certain surfaces broken away and partially sectionalized to illustrate my improved noise reducing arrangement;

Fig. 3 is an enlarged fragmentary view in perspective of the exhaust conduit forming part of my invention.

Referring now to the drawings, 1 have shown therein a domestic clothes dryer 1 which includes a rotatable open ended tumbling basket 2 mounted within a suitable cabinet 3 which encloses it on all sides. The basket is mounted for rotation about a horizontal axis and comprises a cylindrical drum-like member having an outer cylindrical wall 4 and front and rear walls 5 and 6. The outer cylindrical wall 4 of the basket is imperforate over its entire length and on its interior surface is preferably provided with a plurality of clothes tumbling ribs such as illustrated at 7.

Clothes basket 2 is rotatably supported within the outer cabinet 3 by means of a plurality of roller wheels 8, 9, 10 and 11 (see Fig. 2). Wheels 8 and 9 are mounted on an idler shaft 12 and wheels 10 and 11 are mounted on a drive shaft 13. Shaft 12 has no driving connection to it, but shaft 13 is driven from the drive motor 14 of the dryer through a suitable belt and pulley drive 15. As shown, both the idler shaft 12 and the drive shaft 13 are supported adjacent the front and the rear of cabinet 3 by means of suitable bearings mounted in front and rear support plates 16 and 17. Being freely supported on the roller wheels, basket 2 will turn thereon whenever drive shaft 13 is turned by motor 14, the frictional engagement between the side wall of the basket and rollers 10 and 11 causing the basket to turn as the shaft turns. The ratio of the driving and driven pulleys in the drive 15 is suitably chosen so that the basket is rotated at an appropriate speed to provide a tumbling action for articles of clothing placed therein.

In order that a stream of drying air may be introduced and passed through the clothes basket, the basket is apertured at both front and rear ends. Specifically, a central aperture 18 is provided in wall 5 and a similar aperture '19 is provided in wall 6. Rear opening 19 is substantially covered or closed by means of a stationary bulkhead member 20 which is mounted within the dryer cabinet by means of a pair of cross braces 21 and 22. As shown, a suitable clearance is provided between the edge of aperture 19 and the outer flange 23 of bulkhead 20 so that there is no contact between the basket and the bulkheads during rotation of the basket. The front opening of the basket 18 is likewise substantially closed by means of a stationary bulkhead generally indicated at 24. Bulkhead 24 is made up of a number of adjacent numbers including the inner surface 25 of the access door 26 mounted on cabinet 3, a stationary seat 27 for the door, the inner surface 29 of an exhaust duct 30 leading from the basket, and an annular flange 31 mounted on seat 27 and the wall. All of these members cooperate to define a generally circular bulkhead covering opening 18, with flange 31 at its outer edge surrounding the opening. As with the rear bulkhead, a suitable clearance is provided so that there is no rubbing between the edge of opening 18 and the edge of bulkhead 24 during rotation of the clothes basket.

Door 26 includes an outer flat portion 32 and an inwardly extending hollow portion 33 mounted on the flat section. Hollow section 33 extends into the door seat 27 when the door is closed, and the door surface 25 which comprises part of bulkhead 24 is actually the inner wall of this hollow section.

I In the illustrated dryer, the drying air flow is introduced into the basket by means of a screened air inlet 34 in the rear bulkhead 20, passes through the basket, and then out through a screened opening 35 formed in wall 25 of the door section 33. This air movement is elfected in the usual manner by suitable air moving means such as blower 36 driven directly by motor. 14} The air then flows through an opening 37 in door 26 which is aligned with an opening 38 in door seat leading'to duct 30 when the door is closed. It can be seen that wall 25 of door section 33 is, in effect, a shield to prevent the clothes from plugging opening 38 which may, as shown in Fig. 2, be provided with a grille 39 to prevent clothes from falling into ducted during loading and unloading of the dryer. The blower then errhausts "the air from the machine to an outlet condr it or duct'40, which will be more fully described below, and which extends from the blower to" a relatively. large openinglprovided in'the rear of cabinet 3 in communication with the'opcni'ng at the end of the duct 40 A suitable lint trap 42 may bepo'sitioned in any convenient location, such as induct 30" as shown, to perform theu'sual function of removing lint picked up by the aii in the clothes'ba'sket;

The air drawn through the aforementioned duct system by blowerv 36, is pulled into the basket 2 through opening 34' from an intake duct 43 which is mounted on the rear bulkhead 20 and which is open at its lower end 44 within the cabinet 3. Thus, when blower 36 operates, air is drawn into the cabinet through any suitable'openings provided therein for that purpose. (not shown), flows to the inlet 44 of the duct 43, through the duct 43, over a suitable heater 45, through opening 3 4 and into basket'Z. The air flow then passes out through opening 35, the door section 33, duct 34 the blower itself,andduct3j9 to eirhaust opening 41. To prevent any "leakage into the 'baske't'du'ring this operation suitable air seals and 47 are providedfto prevent. leakage through openings 18 and 19 respectively, Seals46.a nd 47 are preferably formed of felt-like material and are biased against the basket so that in addition to serving as seals they also serve as thrust bearings tomaintain the basket in its proper position on rollers 8, 9, and 11. This construction is fully described and claimed in Patent 2,835,048 issued May 20, 1958, to myselfand Robert L. Dunkelman and assigned to the General Electric" Company, owner of the present invention; Operation of the dryer 'to cause the air flow. as described ma be eflected by the setting ofinanual controls 48 which arenermany providedbn the front offa backsplasher w secured to the'cabinetS in' any sinners position, such as to'the' back 'of' the top surface of "the cabinet. t

The operation of motor 14. and of blower 36, the movement of the air within cabinet 3, the operation of the pulley drive '15, and'thei rotation of the drum all combine to produce noise. It is, desirable that this noise levelbe kept to as low an intensity as possible outside the machine for the comfort of any persons near the machine. In this connection, the arrangement now to bedescribed is provided. i

The exhaust duct 'or'conduitetl is formed. as shown of a tubular-portion ofrsiuitable rigid material such as sheet steel. Within, the cabinet 3, duct 4d is. provided with at' least oneopcningfilifand preferably several as shown. Within thcuduca'a th'i-npiece of relatively pliant plastic material 5lisprovided." 'Material Slisof 'a type which is thin enough and soft enoughjto' act as a'mein: brane providing for the'transrnission of sound there:- through but sufficiently non-porous to prevent anyfappreciable passage of gas or air tluereth-rough. One, such material which has'been found suitable for the purpose is the plastic known as polyethylene terephth-alate which is commercially produced by the Du, Pont, Company under the trade name Mylar in very thin. formon the order, for; instance, of. .0Q02 inchim thicknessl he 5 jot his ania m tters with n. dast. tb

Pre erab in was some?! ith he inner hereof to prevent leakage of the gas, and thus forms a diaphragm or membrane 52 over each of the openings 50 in duct 40. The important point is that each opening 50 is covered with a diaphragm 52 which permits the passage of a substantial amount of sound without perm n n Pa a e at an f the s flowing through conduit 40; it will, of course, be understood in this connection that while a solid sheet 51 positioned within dim 40 s en Q i ind dua diaphra m is con: nection with the individual openings 5!} may be provided, or the sheet may be wrapped around the outside of" the conduit 40 with substantial effectiveness insofar as the noise transmission is concerned. In fact, it is conceivable that sheet 51 may itself form part of the duct. However, the arrangement of sheet 51 in a single integral piece within the metal duct 40 represents the presently known most practical method of carryingv out the invention.

In order to absorb the sound transmitted through membranes, 52 to the interior of cabinet 3, there is provided suitable sound absorbing material 53 preferably arranged as shown to cover a substantial part of the bottom of the dryer and to extend part way up the sides as shown at 54. While anysuitabletypeof material may be provided, the arrangement set forth has proved, to .be particularly eflective when the. material is aloosely packed fibrous one suchas fibrous glass.

To illustrate the effectiveness of the arrangement of my invention, a standard dryer, of the type having a /a horse power motor which rotates the basket at 45. r ,p.r n. andwhich moves Bdcubic feet ofair per minute through he stem, s P ov th. my i i e ci v arrang men h du asfmmedntshwt metal V 2 inch inthickness and 4 inchesindiarneter, witha sheet ofpo lyethylene terfephthalatefilm .00025 inch in thickness" positioned within it asshown in Fig, 3, Duct 40 was formedwith 30 openings in it totallingan area of approximately 40 square inches. The noise level resultingvin the vicinityof thernachine from thisarrangement was 12.03 sones.

This figure compares with a. noise level of 16.9 sones for the same dryer whenprovided with only .anordinary duct 49, i.e., with theopeningsv 5 0,membranes 52 and sound absorbing material 53 being omitted as in conventional dryers. Thus, the. improvement in noise. level ff ted: b n a i n s ubstan iate use t an. e ee h t he, i ention; pr v esa in le f est me f mitt n adfab orb ns ai fla ant d m n o e nise f. the ma hine. 1 ha ts a zin t- 3, w heu a n mrz i i s he fl w of; gas or. air through duct4,9.

While in accordance with the patent statutes I have described what at present is considered to be the preferr ed embodiment ofthis invention, it will be obvious to those skilled in the art that various changes and modifications may be made thereinwithout departing from the invention, and it is therefore aimed in the appended claims to cover all such changes and modifications as fall within the truespirit and scope. of nay-invention,

atc aim a e n esire ot e nt rbyta ters Patent of the United States is n ppa at s fi aeftvg fhev aa i nq cn mannin theexhaustin g of gaseous fluid therefrom, a cabinet; en: closing said apparatns, a coirul l .ni t v extendingwithin said bi fof t g a .PQIt mL g t e s l ndha ns ay r na'l t e p i to herexts iqr itaid. a ne d; 'n i t hav p ninsfW-msd. n. t l w i aid abi t mea s. or: auses aseous: n d o p h 'ush e rliwads t to egxhaust d ndmeans m iffli -n ubstan al. t t he? use i; u1t otherwise emerge with the fluid, said muffiing means contprising a sound transmitting membrane of-plastie material srsfiaaseid en nubstan iallyleak-me t e ati n h rsrvit stancla ;masse is puadz. he rba t natsr alt is:

5 posed within said cabinet so as to absorb sound as it is transmitted to the interior of the cabnet through said membrane.

2. In a clothes drying machine, a cabinet for enclosing the component parts of the machine, a conduit extending within said cabinet for at least a portion of its length and having a terminal outlet opening to the exterior of said cabinet, said conduit having a plurality of openings formed in its wall within said cabinet, blower means for causing air to flow into said cabinet and out through said conduit, and means for mufiling a substantial part of the noise of said clothes drying machine which would otherwise emerge from said conduit with the to absorb sound before it leaves said cabinet as it is transmitted into the interior of said cabinet through said membranes.

3. The combination defined in claim 2 wherein said membranes are formed by a sheet of thin pliant plastic material rolled up inside said conduit in snug engagement with the inner surface thereof.

4. The combination defined in claim 2 wherein said membranes are formed of polyethylene terephthalate in thin film form.

5. The combination of claim 2 wherein said mass of sound absorbing material is formed of loosely packed fibrous material.

References Cited in the file of this patent UNITED STATES PATENTS 2,290,259 Vose July 21, 1942 

